If you're truly ready for your son to give up his pacifier, I've got some ideas...
Our son just turned three two days ago. He's been pacifier-free for about a year-and-a-half. How we did it was this;
every third or fourth night, we'd cut a small slice from the tip of the pacifier. (If it's cut straight across, it won't create a choking hazard.)
What that does is make your child realize, over time, that their pacifier is not comforting them anymore, so they find something else to soothe them, (ie; blanket, teddy bear, etc, but hopefully not their thumb!!)
My son did marvelous with this! He's not even a thumb-sucker. I couldn't be more pleased at how this turned out.
Another way I heard of getting rid of the pacifier uses a bit of imagination. It's kind of fun, only if your child understands. Tell your child there are other kids out "there" that need pacifiers. Explain to your child that he can help by giving them his. Take several strings, tie it to the pacifiers, take the pacifiers and your child outside. Find a tree and tie the pacifiers to some branches and explain to your child that the "pacifier fairy" will pick them up while your child is sleeping. When he wakes up the next morning, he'll find they are gone. (This may not work for everyone, but I heard this on a program that deals with such issues for children.)
Well, hopefully these ideas can help you. Good luck and God bless, ls